Needle attachment.



P. H. ADAM-S.

I Suva-H 0 0 Z z I Porter /7. fldu/ms,

Patented Feb. 13,1917.

.JPOBTEB H. ADAMS, OF BROOKLINE, MASSACHUSETTS.

NEEDLE ATTACHMENT.

I Specification of Letters Patent.

Patented Feb. 13, 1917.

Application flled ianuary 27, 1915. Serial No. 4,716.

To all whom it may concern Be it known that I, PORTER H. AnAMs, a

citizen of the United States, residing at- Brookline, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Needle Attachments, of which the following is a specificationf The invention has for an object to give a simple means for eliminating the scratch or grating sound noticeable in the reproduction of phonographic records.

Additional objects, advantages and features of invention will appear from the construction arrangement and combination of parts hereinafter set forth-and shown in the drawings, in Which Figure 1 is an elevation of a needle constituting one form of my invention,

Fig. 2 is a longitudinal sectional view thereof, Fig. 3 is an elevation of a holder and needle engaged therein.

Fig. 4 is a detail of a modification of the needle.

Fig. 5 is a detail side view of the needle holder,

Fig. 6 is a deta l front view thereof,

Fig. 7 is a detail end view of the needle holder.

There is illustrated a sound box 10, carried by the sound arm 11 in a familiar manner, a stylus bar 10 being mounted on the box having a needle holder at the lower end. The sound box construction including the stylus and its mounting are of any usual construction, and need not be modified. I have, however, shown a form of holder especial useful in "connection with my form of needle, and which I believe.will embody principles practically essential in the use of a needle of this kind, the holder being rigidly secured in the usual position on the stylus bar, or formed integrally therewith.

The holder in the present case is formed with a needle receiving socket of larger diameter than the ordinary, and comprises a stationary jaw portion 12 the shank of which forms a continuation of the stylus bar. This jaw is formed with a longitudinal channel 13 having a rounded bottom, and open on one side of the jaw, a bridge 14 being formed thereover intermediately-of its length, in which there is engaged a binding screw 15 hearing against a clamping plate 16 movable toward and away from the bottom of the. channel 13 and having a longitudinal transversely curved groove 16 on its inner side opposed to the bottom of the channel. This plate is supported by a spring 18, which tends to hold the plate at theouter limit of its movement yieldably to the pressure of the screw. The spring is engaged upon the back of the plate and fixed to the base of the jaw 12 and may be also fixed on the plate 16.

Engaged in the holder there is a needle 20, comprising a steel-point piece 21, somewhat longer than the ordinary needle customarily employed in disk record machines at present, and it is provided with a rubber jacket 22, completely encircling the needle point body throughout the major part of its length, stopping short. of both ends, the point proper of the piece 21 being well projected therefrom. In practice the needle is about (one sixteenth) of an inch in diameter from its inner ends to the outer end. of the jacket, and in the neighborhood of one inch in length, the point proper projecting about three sixteenths of an inch from the jacket. This point may be of the usual taper and sharpness. The jacket is of a uniform thickness throughout its length and is approximately (one sixteenth) of an inch thick. The needle with its jacket is presented in t e holder while the screw 15 is at the outer lmit of its movement and the screwthenoperated to press the plate 16 firmly against the jacket of the needle, by which means it is held securely in place.

I have found it desirable to form the needle and jacket substantially of the length shown, although it may be found possible or desirable to vary these proportions. The quality of the jacket has a determining effect, as with a very soft rubber for instance, it would be desirable to have a long jacket; on the other hand, a jacket may be used having a reduced resilience which would not require to be quite so long. For small rooms it is thought desirable to use a soft rubber jacket, while for large halls it may be that a harder jacket would be desirable, although the efliciency of the needle with a soft jacket is such that it will give a strong reproduction of a record. In practice the resilience of the jacket has approximated that of the tread rubber of motor tires.

In one use ofthe device, the projecting blunt end of the needle is allowed to engage against the inner end of the holder, in another, the inner end of the needle is entirely covered by the jacket, as in Fig. t, whereby the needle is entirely isolated from metallic connection with the diaphragm. The needle:- with its inner end exposed may also be adjusted with its inner end out of contact with the holder when clamped, if desired, lPhe attainment of entire insulation of the sound box, diaphragm and connections between the needle and diaphragm from the transmission of those jars or vibrations which are beyond the range ot harmonic sound is thus attained, and in practice' the device has been r'ound to give a highly satisfactory rendition ol the record propel. At the. same time the prior dilliculties in providing simple and practicable mountings and connections under this con dition have been eliminated. As before stated, the ordinary mounting for the needle holder may be employed, without cushioning. and the connections between the holder and diaphragm may'be of any familiar :l'orm, also requiring nocushioning.

Some of the simpler mountings and con nections of the earlier stages of the art are available for use with my invention, with the best results, and a great cheapening of the cost.

It is possible to modify the embodiment of my invention, and to use it in other ways than specifically indicated herein, as will be understood.

My needle With the insulating jacket may be inserted in the ordinary needle holder and held by the usual set screw there provided, butv with the character of jacket required to produce the effect desired, such screw tends to pass through the jacket and engage the needle directly, thus completing av metallic connection from the needle to the stylus bar and defeating the purpose of the invention. '.l.herefore, the invention appears to necessarily involve a holding appliance in which a large area oi the jacket is compressed to secure the needlein the holder, in practice the needle having been made in excess of one inch in length, and the jacket about one inch inlength.

What is claimed:

reproducing device lor machines ol' the kind indicated including a stylus bar, a me dle holder rigidly carried thereby. compris ing a body having a longitudinal channel opening on its outer end, an elongated clamping plate alined with the channel and movable to engage a. needle interposed in the channel, a leaf spring attached to the body and to the plate, shaped to hold the plate yieldably at the outer limit of its movement, an extension of the body disposed over the channel and a screw engaged the-rethrough impinging upon the plate.

In testimony whereof I have afiixed my signature in presence of two witnesses.

PORTER H. ADAMS.

Witnesses:

SEWALL C. BROCKETT, FRANK S. DELAND. 

